JPH03187066A - Optical information storage medium driving device - Google Patents

Abstract

PURPOSE:To shorten the time required for retrieval by detecting the movement speed in the radial direction of an optical head and comparing it with a set speed and keeping a rotation driving signal to an information storage medium rotating means at the just preceding value at the time when the detected movement speed is higher. CONSTITUTION:When the speed at which an optical head 3 is moved in the radial direction by a moving means 4 exceeds the value set to a set speed source 10 in accordance with the attenuation factor characteristic of track cross components required for accurate rotation control information RC of a frequency filter 5, the rotation driving signal is kept at the value just preceding the excess of the movement speed over the set speed by a holding circuit 12 and is supplied to a rotating means 2. Consequently, track cross components have not a bad influence upon the rotation driving signal and the variance of the rotative speed of the means 2 is prevented to quickly adjust rotation after the end of retrieval, and the time required for retrieval is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to rotation control of an optical information storage medium drive device, and particularly to rotation control during a search (access) operation.

[Conventional technology]

In recent years, many write-once or rewritable optical information storage media have been proposed that are compatible with so-called compact discs and are capable of recording and/or reproducing information using a common recording and reproducing device. By the way, with a compact disc, absolute position information (absolute address) on the disc and disc rotation control information can be obtained from the playback signal, but with recordable or rewritable information storage media, the playback signal is usually not available in an unrecorded state. Therefore, absolute position information or rotation control information cannot be obtained from the reproduced signal.

Therefore, a method has been proposed for obtaining absolute position information or rotation control information even in an unrecorded state in a conventional write-once type or rewritable type information storage medium.

One such method, the track modulation method (see Japanese Patent Application Laid-Open No. 64-39632), modulates the free space between the frequency band for focus and tracking control and the frequency band of the reproduced signal. The absolute position information or the rotation control information is track modulated, that is, the track consisting of the guide groove etc. is deflected in the radial direction of the disk at a predetermined period according to the rotation control information, or the track width is changed at a predetermined period. This is recorded by changing the .

Hereinafter, a conventional rotation control operation using the above track modulation method will be explained with reference to the drawings.

FIG. 2 is a configuration diagram of a rotation control section of a conventional optical information storage medium drive device. An information storage medium 1, such as a write-once type or a rewritable type, is attached to a rotating means 2, such as a spindle motor, and rotated.

The rotation control information RC written in the information storage medium 1 by track modulation is transferred from the optical hand 3 to the information storage medium l.
The tracking error signal TER is included in the tracking error signal TER for detecting the positional deviation in the direction orthogonal to the track of the light beam irradiated to the optical head 3 based on the reflected light from the information storage medium 1. This is what is read by. The optical head 3 is moved in the radial direction of the information storage medium 1 by an optical head moving means 4.

The tracking error signal TER is sent to the frequency filter 5, where the rotation control information RC is extracted.

This rotation control information RC is sent to the control circuit 6 and compared with a reference signal sent from a reference signal source 7. Then, a rotation drive signal corresponding to the comparison result is sent from the control circuit 6 to the rotation means 2.
The rotation speed is adjusted so that the reference signal and rotation control information RC match. In this way, the rotation of the information storage medium 1 is controlled so that it always has a predetermined rotational speed.

In the above track modulation method, the focus and trunking control band is around DC-KHz, and the frequency band of the reproduction signal is from several 100 KHz to several M)lz.
The area that does not overlap with nearby bands is the rotation control information RC.
Specifically, for example, 22.0
5KHz is selected.

[Problem to be solved by the invention]

By the way, during a search operation, the optical head 3 is moved in the radial direction of the information storage medium 1 by the optical head moving means 4. At this time, as the optical head 3 crosses the track on the information storage medium 1, a track cross component having a much larger amplitude than the rotation control information RC appears in the tracking error signal TER.

Here, the tracking error signal TER when the search operation is not performed is shown in FIG. 3, and the tracking error signal TER during the search operation is shown in FIG. The frequency of the track-crossing component is determined by the speed at which the track crosses, e.g.
20000) 20 KHz when crossing the rack in 1 second
becomes.

In other words, when the moving speed of the optical head 3 increases during a search operation, there is a risk that a track cross component whose frequency is approximately equal to the rotation control information RC and whose signal amplitude is larger than the rotation control information RC may be mixed into the tracking error signal TER as a disturbance. There is. When the frequencies are close to each other in this way, the rotation control information RC and the track cross component cannot be separated by the frequency filter 5, and the rotation drive signal of the rotation means 2 output from the control circuit 6 is also affected by the track cross component. It is something.

As a result, during the search operation, especially when the moving speed of the optical head 3 is high, the rotation of the rotating means 2 becomes unstable, and the rotation does not settle properly after the search operation is completed, which increases the time required for the search. There was a problem.

[Means to solve the problem]

In order to solve the above-mentioned problem, an optical information storage medium drive device according to the present invention irradiates a light beam onto an information storage medium, such as a write-once type or a rewritable type, on which rotation control information is recorded in advance, and performs recording and/or recording. Alternatively, an optical head for reproducing, an optical head moving means for moving the optical head in the radial direction of the information storage medium, a rotation means for supporting and rotating the information storage medium, and a tracking error signal obtained from the information storage medium. An optical information storage medium drive comprising a signal processing means for obtaining the rotation control information, and a control means for supplying a rotation drive signal to the rotation means to control the rotation speed based on the rotation control information from the signal processing means. In the apparatus, a speed detecting means for detecting the moving speed of the optical head in the radial direction, a speed comparing means for comparing the moving speed detected by the speed detecting means and a set speed, and the moving speed is set by the speed comparing means. The present invention is characterized by comprising a holding means for holding the rotational drive signal from the control means and outputting the held value to the rotation means when it is determined that the rotational speed is greater than or equal to the rotational speed.

[For production]

According to the above configuration, when the moving speed of the optical head in the radial direction exceeds the set speed, the rotational drive signal for driving the rotating means is held at the value immediately before the moving speed exceeded the set speed, and Since the rotational speed of the information storage medium is kept at a constant value during the period when the speed is higher than the set speed,
The rotational speed during the search operation remains constant regardless of the track cross component described above. As a result, the rotational speed is quickly stabilized after the search ends.

〔Example〕

An embodiment of the present invention will be described below based on FIG.

As shown in FIG. 1, the optical information storage medium drive device according to the present embodiment has a rotating means such as a spindle motor that supports and rotates an information storage medium 1, such as a write-once type or a rewritable type, as in the conventional example. 2, an optical head 3 that records and/or reproduces information by irradiating the information storage medium 1 with a laser beam, and an optical head moving means that includes a linear motor or the like that moves the optical head 3 in the radial direction of the information storage medium 1. 4, a frequency filter 5 as a signal processing means for obtaining rotation control information RC of the information storage medium 1 from the tracking error signal TER detected by the optical head 3, and rotation control information RC obtained by the frequency filter 5 and a reference signal. A control circuit 6 is provided as a control means for comparing the reference signal supplied from the source 7 and supplying a rotation drive signal to the rotation means 2 so that the rotation control information RC and the reference signal match.

Further, this optical information storage medium driving device includes a speed detection circuit 8 as a speed detection means for detecting the moving speed of the information storage medium 1 of the optical head 3 in the radial direction by the optical head moving means 4; A speed comparison circuit 11 as a speed comparison means for comparing the moving speed of the optical head 3 detected by the set speed with the set speed supplied from the set speed source 10.
Then, a signal indicating that the moving speed of the optical head 3 in the radial direction of the information storage medium 1 is equal to or higher than the set speed is sent to the speed comparison circuit 1.
1, the rotational drive signal from the control circuit 6 is held at the value immediately before the above-mentioned moving speed exceeds the set speed, and the held value is output to the rotation means 2, which causes the rotation means 2 to rotate. Holding circuit 1 as a holding means to keep the speed constant
2.

A track is formed in advance on the information storage medium 1 by a guide groove or the like (not shown), and this track is formed on the information storage medium 1 in advance.
Rotation control information RC and absolute position information are recorded on the information storage medium 1 by track modulation by deflecting in the radial direction or changing the width of the track.

In the speed detection circuit 8, for example, the moving speed of the optical head 3 is determined by detecting the period of the track cross component of the reproduction signal or the tracking error signal TER,
The optical head 3 is moved by an appropriate method such as estimating the moving speed of the optical head 3 from a drive signal applied to the optical head moving means 4.
The moving speed of the vehicle is now detected.

Further, the set speed of the set speed source 10 is set according to the attenuation characteristic of the frequency filter 5. That is, for example, in order to obtain accurate rotation control information RC, the track cross component is
/10 or less, the attenuation rate of the track cross component by the frequency filter 5 should be 1.
The speed at which a frequency of 710 is given may be set as the set speed.

In the above configuration, the information storage medium 1 is rotated by the rotation means 2 based on, for example, CLV (constant linear velocity) control. For example, if the information storage medium 1 is a write-once type, recording is performed by irradiating the information storage medium I with a laser beam from the optical head 3. For example, if the information storage medium l is a rewritable type that utilizes the magneto-optical effect, a magnetic field is applied to the information storage medium 1 by a magnetic head (not shown) while the information storage medium 1 is irradiated with a laser beam from the optical head 3. Recording is performed by applying the voltage.

On the other hand, information is reproduced by irradiating the information storage medium 1 with a laser beam from the optical head 3 and detecting the reflected light from the information storage medium 1 by the optical head 3.

Also, a focus error signal and a tracking error signal T are generated based on the reflected light from the information storage medium 1 during recording or reproduction.
ER is generated and based on these signals the optical hand 3
Focusing and tracking are controlled by driving the objective lens.

The above tracking error signal TER is filtered by the frequency filter 5.
The rotation control information RC is extracted here. This rotation control information RC is sent to the control circuit 6 and compared with a reference signal supplied from a reference signal source 7. The control circuit 6 sends a comparison result, that is, a rotation drive signal according to the difference between the rotation control information RC and the reference signal to the holding circuit 12 .

Further, the speed detection circuit 8 detects the moving speed of the optical head 3 in the radial direction of the information storage medium 10, and the speed comparison circuit 1
1, the moving speed of the optical head 3 in the radial direction of the information storage medium 1 is compared with a set speed from a set speed source 10. When the moving speed of the optical head 3 in the radial direction of the information recording medium 1 is less than the set speed, the rotation drive signal from the control circuit 6 is directly transmitted to the rotating means 2 via the holding circuit 12.
The rotation speed of the rotation means 2 is controlled so that the rotation control information RC matches the reference signal.

On the other hand, when the moving speed of the optical head 3 in the radial direction exceeds the set speed during the search, the holding circuit 12 holds the rotational drive signal immediately before the moving speed of the optical head 3 exceeds the set speed. During the period when the moving speed of the head 3 is equal to or higher than the set speed, a constant rotation drive signal held by the holding circuit 12 is supplied to the rotating means 2. As a result, when the moving speed of the optical head 3 is equal to or higher than the set speed, in other words, when the attenuation rate of the track cross component by the frequency filter 5 exceeds, for example, 1/10, the rotational speed of the rotating means 2 is kept constant. be done.

As a result, the track cross component does not adversely affect the rotational drive signal, and fluctuations in the rotational speed of the rotating means 2 are prevented. As a result, the rotation of the rotating means 2 can be quickly stabilized after the search ends, and the time required for the search is shortened.

Note that during the search, the optical radar 3 is guided to a desired absolute position based on the absolute position information recorded on the information storage medium 1 in advance.

〔Effect of the invention〕

As described above, the optical information storage medium drive device according to the present invention includes a speed detecting means for detecting the moving speed of the optical head in the radial direction, and a comparison between the moving speed detected by the speed detecting means and the set speed. and holding means for holding the rotation drive signal from the control means and outputting the held value to the rotation means when the speed comparison means determines that the moving speed is equal to or higher than the set speed. The configuration is as follows.

As a result, when the moving speed of the optical head in the radial direction exceeds the set speed, the rotational drive signal that drives the rotating means is held at the value immediately before the moving speed exceeded the set speed, and the rotational speed of the information storage medium is increased. I tried to keep it at a constant value, so
The rotational speed during the search operation remains constant regardless of the track cross component described above. As a result, the rotational speed is quickly stabilized after the search ends, making it possible to shorten the time required for the search.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an optical information storage medium drive device according to an embodiment of the present invention. 2 to 4 show conventional examples. FIG. 2 is a schematic configuration diagram showing an optical information storage medium drive device. FIG. 3 is an explanatory diagram showing a tracking error signal when no search operation is performed. FIG. 4 is an explanatory diagram showing a tracking error signal during a search operation. 1 is an information storage medium, 2 is a rotation means, 3 is an optical head, 4
5 is an optical head moving means, 5 is a frequency filter (signal processing means), 6 is a control circuit (control means), 8 is a speed detection circuit (speed detection means), 11 is a speed comparison circuit (speed comparison means), and 12 is holding It is a circuit (holding means).

Claims (1)

[Claims] 1. An optical head that performs recording and/or reproduction by irradiating a light beam onto an information storage medium on which rotation control information is recorded in advance;
optical head moving means for moving the optical head in the radial direction of the information storage medium; rotation means for supporting and rotating the information storage medium; and signal processing for obtaining the rotation control information from a tracking error signal obtained from the information storage medium. and a control means for controlling the rotational speed by supplying a rotational drive signal to the rotational means based on rotational control information from the signal processing means, comprising: a speed detecting means for detecting the moving speed of the vehicle; a speed comparing means for comparing the moving speed detected by the speed detecting means with a set speed; and a speed comparing means that determines that the moving speed is equal to or higher than the set speed. 1. An optical information storage medium driving device comprising: holding means for holding a rotational drive signal from the control means and outputting the held value to the rotation means.